The electromagnetic field around us.We can't see them with the naked eye, but this does not mean they can not be used as an energy source. Scientists created an equipment which can charge AA-battery by making use of electromagnetic field produced from vehicles and electronic products.
The amount of energy collected by the Electromagnetic Harvester is still a major problem temporarily. A "finger" battery can support a day of electricity consumption of electronic equipment.
According to Dennis Siegel, students from the University of the Arts, in order to obtain power, Electromagnetic Harvester must be closed to the computer, mobile phone or into the subway. Once the device reaches a sufficiently strong magnetic field area, the LED lamp of the device will emit red light, that is charging.